Add an iov_iter to the unions in ceph_msg_data and ceph_msg_data_cursor.
Instead of requiring a list of pages or bvecs, we can just use an
iov_iter directly, and avoid extra allocations.
Note that we do assume that the pages represented by the iter are pinned
such that they shouldn't incur page faults.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
include/linux/ceph/messenger.h | 5 +++
include/linux/ceph/osd_client.h | 4 +++
net/ceph/messenger.c | 64 +++++++++++++++++++++++++++++++++
net/ceph/osd_client.c | 27 ++++++++++++++
4 files changed, 100 insertions(+)
diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 9fd7255172ad..c259021ca4a8 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -123,6 +123,7 @@ enum ceph_msg_data_type {
CEPH_MSG_DATA_BIO, /* data source/destination is a bio list */
#endif /* CONFIG_BLOCK */
CEPH_MSG_DATA_BVECS, /* data source/destination is a bio_vec array */
+ CEPH_MSG_DATA_ITER, /* data source/destination is an iov_iter */
};
#ifdef CONFIG_BLOCK
@@ -224,6 +225,7 @@ struct ceph_msg_data {
bool own_pages;
};
struct ceph_pagelist *pagelist;
+ struct iov_iter iter;
};
};
@@ -248,6 +250,7 @@ struct ceph_msg_data_cursor {
struct page *page; /* page from list */
size_t offset; /* bytes from list */
};
+ struct iov_iter iov_iter;
};
};
@@ -605,6 +608,8 @@ void ceph_msg_data_add_bio(struct ceph_msg *msg, struct ceph_bio_iter *bio_pos,
#endif /* CONFIG_BLOCK */
void ceph_msg_data_add_bvecs(struct ceph_msg *msg,
struct ceph_bvec_iter *bvec_pos);
+void ceph_msg_data_add_iter(struct ceph_msg *msg,
+ struct iov_iter *iter);
struct ceph_msg *ceph_msg_new2(int type, int front_len, int max_data_items,
gfp_t flags, bool can_fail);
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 6ec3cb2ac457..ef0ad534b6c5 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -108,6 +108,7 @@ enum ceph_osd_data_type {
CEPH_OSD_DATA_TYPE_BIO,
#endif /* CONFIG_BLOCK */
CEPH_OSD_DATA_TYPE_BVECS,
+ CEPH_OSD_DATA_TYPE_ITER,
};
struct ceph_osd_data {
@@ -131,6 +132,7 @@ struct ceph_osd_data {
struct ceph_bvec_iter bvec_pos;
u32 num_bvecs;
};
+ struct iov_iter iter;
};
};
@@ -501,6 +503,8 @@ void osd_req_op_extent_osd_data_bvecs(struct ceph_osd_request *osd_req,
void osd_req_op_extent_osd_data_bvec_pos(struct ceph_osd_request *osd_req,
unsigned int which,
struct ceph_bvec_iter *bvec_pos);
+void osd_req_op_extent_osd_iter(struct ceph_osd_request *osd_req,
+ unsigned int which, struct iov_iter *iter);
extern void osd_req_op_cls_request_data_pagelist(struct ceph_osd_request *,
unsigned int which,
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 6056c8f7dd4c..cea0d75dfc49 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -964,6 +964,48 @@ static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data_cursor *cursor,
return true;
}
+static void ceph_msg_data_iter_cursor_init(struct ceph_msg_data_cursor *cursor,
+ size_t length)
+{
+ struct ceph_msg_data *data = cursor->data;
+
+ cursor->iov_iter = data->iter;
+ iov_iter_truncate(&cursor->iov_iter, length);
+ cursor->resid = iov_iter_count(&cursor->iov_iter);
+}
+
+static struct page *ceph_msg_data_iter_next(struct ceph_msg_data_cursor *cursor,
+ size_t *page_offset,
+ size_t *length)
+{
+ struct page *page;
+ ssize_t len = iov_iter_get_pages(&cursor->iov_iter, &page, PAGE_SIZE,
+ 1, page_offset);
+
+ BUG_ON(len < 0);
+
+ /*
+ * The assumption is that the pages represented by the iov_iter are
+ * pinned, with the references held by the upper-level callers, or
+ * by virtue of being under writeback. Given that, we should be
+ * safe to put the page reference here and still return the pointer.
+ */
+ VM_BUG_ON_PAGE(!PageWriteback(page) && page_count(page) < 2, page);
+ put_page(page);
+ *length = min_t(size_t, len, cursor->resid);
+ return page;
+}
+
+static bool ceph_msg_data_iter_advance(struct ceph_msg_data_cursor *cursor,
+ size_t bytes)
+{
+ BUG_ON(bytes > cursor->resid);
+ cursor->resid -= bytes;
+ iov_iter_advance(&cursor->iov_iter, bytes);
+
+ return cursor->resid;
+}
+
/*
* Message data is handled (sent or received) in pieces, where each
* piece resides on a single page. The network layer might not
@@ -991,6 +1033,9 @@ static void __ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor)
case CEPH_MSG_DATA_BVECS:
ceph_msg_data_bvecs_cursor_init(cursor, length);
break;
+ case CEPH_MSG_DATA_ITER:
+ ceph_msg_data_iter_cursor_init(cursor, length);
+ break;
case CEPH_MSG_DATA_NONE:
default:
/* BUG(); */
@@ -1038,6 +1083,9 @@ struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor,
case CEPH_MSG_DATA_BVECS:
page = ceph_msg_data_bvecs_next(cursor, page_offset, length);
break;
+ case CEPH_MSG_DATA_ITER:
+ page = ceph_msg_data_iter_next(cursor, page_offset, length);
+ break;
case CEPH_MSG_DATA_NONE:
default:
page = NULL;
@@ -1076,6 +1124,9 @@ void ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor, size_t bytes)
case CEPH_MSG_DATA_BVECS:
new_piece = ceph_msg_data_bvecs_advance(cursor, bytes);
break;
+ case CEPH_MSG_DATA_ITER:
+ new_piece = ceph_msg_data_iter_advance(cursor, bytes);
+ break;
case CEPH_MSG_DATA_NONE:
default:
BUG();
@@ -1874,6 +1925,19 @@ void ceph_msg_data_add_bvecs(struct ceph_msg *msg,
}
EXPORT_SYMBOL(ceph_msg_data_add_bvecs);
+void ceph_msg_data_add_iter(struct ceph_msg *msg,
+ struct iov_iter *iter)
+{
+ struct ceph_msg_data *data;
+
+ data = ceph_msg_data_add(msg);
+ data->type = CEPH_MSG_DATA_ITER;
+ data->iter = *iter;
+
+ msg->data_length += iov_iter_count(&data->iter);
+}
+EXPORT_SYMBOL(ceph_msg_data_add_iter);
